It is proposed to undertake a comprehensive nationwide study of the patterns of cancer care in clinical and research Radiation Therapy, with the object of improving availability and accessibility of quality radiation therapy throughout the country. Through this study the information needed to determine the extent to which quality care is not readily available will be obtained by defining criteria for optimal radiation therapy care, and by documenting the current status of radiation therapy in the light of these criteria. A formalism has been developed and is described here to obtain factual and complete information in this regard, covering all sectors of the radiation therapy community. By organizing the study within the framework of the American College of Radiology which has a national basis and represents both full time and part time radiation therapists, the support of all sectors of the radiation therapy community can be enrolled. The study will also identify and analyze those organizations and institutions which support radiation therapy care. From the information obtained, and analyzed, policy and program recommendations will be prepared and areas requiring further investigation and development will be identified in order to improve radiation therapy care for a significant number of cancer patients.